Telegraph repeater



1934- w. s. SPARKS 1,969,483

TELEGRAPH REPEATER I Filed Nov. 50. 1929 3 Sheets-Sheet 1 LR: X LRz.

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TELEGRAPH REPEATER Filed Nov. 50. 1929 5 Sheets-Sheet 2 Qvwzntoz W. 6. Spar/2s $51, 1% WW Aug. 7, 1934. w. s. SPARKS TELEGRAPH REPEATER s Sheets-Sheet 3 Filed NOV. 30. 1929 HF i avweutoz 14 6. .fipar/ns Patented Aug. 7, 1934 smms TELEGRAPH REPE 'rEn William SuSparks, Brooklyn, N. Y., assignor to The Western Union Telegraph Company, New 7 I l Q York, N. Y., a corporation of-New York I Application November 30, 1929, Serial No. 410, 752

14 Claims. (c1. ne -71) This invention relates to a telegraph, system and moreparticularly to improvements in arrangements for repeating signals in such systems. It is applicable to single line repeaters,- full duplex repeaters or duplex half repeaters and is especially advantageous in connection with telegraph systems employing machine transmitting and receiving apparatus such as printing telegraph machines operating at a high speed, although it is not limited thereto.

In printing telegraph systems as commonly employed the signals are transmitted in accordance with a five. or six unit code composed of combinations of marking and spacing impulses. 15 The signals may be transmitted through the keyboard of a printing machine or by a tape transmitter or other form of storage transmitter and themarking and spacing impulses comprising each signal train are-transmitted at a predetermined speed .and are .of equal duration. The printing mechanism operates in synchronism with the transmitting apparatus and responds to each signal combination to effect the printing of a particular letter or character. r

For the sake of economy it is desirable to operate the system at the maximum speed at which the printing mechanism will satisfactorily operate, which is considerably above the speeds heretofore employed in telegraph transmission. At such speeds only a limited and definite time is available for the marking and spacing impulses to accomplish their function. Any distortion of the signals, such as the lapping over of a marking signal into the period allotted to a spacing signal or the shortening of a signal impulse of either spacing or marking character may cause the improper operation of the printing mechanism. It is essential therefore, for high speed operation that marking and spacing impulses of substantially equal duration should be transmitted to the printing mechanism.

There is a tendency, however, inherent in the usual telegraph repeater construction; due to time consumed by the various relay tongues in travelling between their stationary contacts, for the marking and spacing impulses to be repeated of slightly different length from the received impulses. This distortion of the signal impulses is accumulative and in long lines 'involvingha number of repeating sets it becomes a source of'serious difiiculty.

Accordingly, it is one of the objects of the present invention to produce a high speed telegraph repeater'in which the marking and spacing signals transmitted by the repeater will be tents of the controlling relay'is substantially abergized.

over, the repeating relay is rendered extremely sent.

A still further object is to provide a novel locking arrangement for preventing the repeating of spacing signals back overthe line from which thesignals arebeing received and to reduce -"the period during which the locking winding is en- Other objects and advantages will appear more fully from the detailed description of invention hereinafter given. r

Inaccordancewith my invention I employ a polarized transmitting or repeating relay-having :a source of potential of 'the same polarity joined to each terminal thereof, one terminal being grounded throughian appreciable resistance, and the other terminal being grounded, in response to spacing signals, through the spacing contact of the receiving relay. j A locking circuit is also provided to prevent repetitionof the signals into the line from which they are being received, the locking circuit-being controlled entirely through the marking contact ofthe line relay.- With this arrangement only twocontacts are required ,on the line relay to control both the locking circuit and the reversals of current in the repeating relay. Thenecessity of employing double contact .relays with slow acting spring contacts ,is. thus avoided'andan arrangement is provided which enables the repeated signals to be of exactly the same duration as the received signals. Morerapid 'in'ioperation since the spacing current through the windingthereof is entirely removed when the marking .current'is applied'and .vice versa, so that neither the spacing nor the marking currents have'any biasing force to overcome. ,105

' The repetition-of marking and'spacing signals of equal lengths with the received signals is accomplished by making the travel time of the tongue of the receiving relay, in a spacing direction, a part of the marking-signal and the travel time of the tongue of the repeating relay, in a marking direction, a part of the spacing signals. The constants of the system may be adjusted so that the tongues of both relays have equal travel periods whereby one exactly compensates 2 except employing a polarizedpolechanging- ..t ransmitting relay 'IRi.

relay;

Figure 4 is a circuit arrangement of a terminal duplex set; and

Figure 5 is an arrangement permitting the connection of a plurality" o'f"sending -andreceiving legs to a terminal duplex set." Referring first to Figures 1 and-2, single lines L1 and L2 are shown associated with-a single line-through repeater, the parts. of which are diagrammatically represented; The line L1 is connected to one terminal of the winding of the line magnet 10 of the line relay LRI', the-opposite terminal of the winding of theline magnet being connected to the contact tongue of the transmitting relay TR.2.' The marking contact of transmitting relay TRz is' connected to a grounded source of potential, such as a generator '11. Likewise line L2 is connected through the winding of the line magnet 12, of the linerelay LRz, to the tongue of the transmitting relay TR1, the marking contact-of which is joined to the grounded source potential -13.- The line relays LRi' and LRz are neutralrelays and the transmitting relays TRi' and 'I'Rz are polarized relays, although it is to be understood that the line relays may also 'be polarized if s The front or marking contact of line relay LR'i is connected through a resistance'm to a grounded 'sourceof'potenti'al 15 and al'soto one terminal of the locking winding lfi of the'line relay LRz, the opposite terminal of which is grounded.

spacing contact of line relay LR: is'connected to comes a part of the preceding spacing signal.

a source of potential 24, oflike polarity to the generator 21, through a'resistance 25'. The con- 'tact is also connected through -..the."winding .of transmitting may TRz'and resistance 23 to the ground at 22. The tongues of relays LRr'an'd LRz'are grounded at 26'and 27respective'lylz'.

' The operation of therepeate'r is" as follows? .If a markingsignal:isEbeing transmittedqsover line L1 the armature tongueof each of therelays will be .on i-tsimarking contact as shown in Fig- .iure l. The locking magnets lG and 19 will be short circuited through markingicontacts and :tongues of the line relaysLRlcand LRz respec- -tively,;and the locking windings. will, thereiore, unenergizedzg Thewindingsiof transmitting 'ing'of transmitting relay TRi in a marking direc- -will-be repeated'over the lines. i .Uponcontact of thetongue of relay LE1 with its -force fromthe relay LRz'iS simultaneous with the relays TR1 and TRz will be energized from the generators 21 and 24 respectively, the current flowing through the operating windings thereof in a marking direction, to the ground 22.

If a spacing signal is transmitted over line L1 the tongue or" line relay LRI, in response thereto, will move to its spacing contact. Asitleaves the marking contact the short circuiting ground 26 is removed fromthe locking magnet 16 and the source of potential 15 is applied thereto, thus locking the tongue of relay LRz against its marking contact so as to prevent the repetition of the spacing signal back over the line L1. When the tongue of the relay. LR; reachesits spacing contact the genierator 21 1s grounded therethrough and there 20 by 'in efiectremoved from the winding of the At the same time the current flowing from the generator 24 through the Winding of transmitting relay IE2 is partially diverted from the ground 22 and flows through :the'windin'g of transmitting relay TRi in a spacing direction and thence tothe ground 26 through the tongue of the relay LR1. The tongue of transmitting relay TRi is thus moved'to its spacing contact to repeat the-spacing signal over the. line L2 I fIt will be noted thatthe tongue of relay LE2 was locked on its marking contact prior to the retransmission of thespacing signal through the line magnet 12 and that the travel time of the ,195 tongue ofrelayLRgin a spacing direction, was a partof themarking signal. The travel time of thetongue of the transmitting relay TRi, in a spacing direction was not a part ofthe marking 7 signal, however, since the spacing signal was repeated over line Lzas soon as the tongue of relay TRileft its marking contact. It should=be further noted that, at the instant spacing battery 24 was applied to the winding of The reversal of current through the transmit-:

=tin'g relay, was accomplished through a single'contact of the relay LRi leaving the other contact free to control the locking magnet 16. These features permit high speed operation of the'repeater.

'Uponthe transmission of a marking signal over I 25 the line L1 the tongue of relay LE1 leaves the spacing contact-and in so doing removes the short circuiting ground 26 from the generator 21, there- 'by applyingthis sourceof potential to the wind- 33B tion' and thus causing the tongue thereof to move to its markingcontact. The marking signal is '-not repeated to the line L2, howevenuntil the tongue of'relay TRi reaches its marking contact, whereby the travel time of the relay tongue be- By adjusting the constants of th'e' system so that markingand spacing signals .iof equal durations marking contact the sourceof potential l5.is

grounded-so that the current falls to zero in-the locking winding 16. The-removal ,of-the locking repetition of the marking signal over line L2, since the travel time of the tongues of relays 111311 and "1R1 is equal. This permits the maximum time to be available in which a break signal, transmitted over line L2, will be effective. Thus, if the opera tor at the end of the line L2, attempts to break in on the line during the period when the tongue Therefore, any overlap of the energization of the locking magnet 16 on the marking signal being repeated over line L2 will reduce the available period during which the operator at the end of L2 may break in on the line.

Since the break signal is' limited to a short length by the machine transmitter, it may not be properly repeated to the line L1, if the tongue of relay LE2 is locked on its marking contact for any prolonged part of the marking signal being repeated to the line L2.

It should be noted that the tongues of the relays LRl and LE2 do not interrupt any inductive circuits but serve only to ground the generators 15, 18, 21 and 24. Consequently there will be no appreciable sparking at the contacts of these relays.

In Figure 2 I have shown my invention applied to a duplex half repeater. The single line SL is connected through the operating winding 30 of the pole changer PC and to the marking contact of the transmitting relay TR, the tongue of relay TR being grounded through a source of potential 31. The duplex line BL is connected through the difierential winding of the line relay LR to the artificial line AL. The midpoint of the winding of relay LR is connected, in the usual manner, to the tongue of the pole changer PC.

'The 'marking contact of relay LR is connected to a source of potential 32 through a resistance 33 and the spacing contact is similarly connected to a source of potential 34 through a resistance The marking contact is also connected to one terminal of the locking winding 36 of the pole changer, the opposite terminal of which is grounded. The spacing contact of relay LR is connected to one end of the winding of the transmitting relay TR, the opposite end of which 'is connected througha resistance 37 to a source of potential 38 and also to the ground at 39 through a resistance 40. The tongue of relay LR is grounded at 41.

The operation of the system is similar to the single line repeater. When marking signals are transmitted over the duplex line DL the tongues of all of the relays are on their marking contacts. The locking winding 36 of the pole changer is short circuited through the tongue of the line relay LR to the ground 41. The winding of transmitting relay TR is supplied with operating current from the generator 34.- to the ground 39, the current being in a marking direction.

' Upon the receipt of a spacing signal over the duplex line the tongue of the line relay leaves its marking contact and in so doing removes the ground 41 from the locking winding 36, thereby permitting the energization thereof from the generator 32. As soon as the tongue of the line relay reaches its spacing contact the generators 3e and 38 are,v connected to the low resistance ground i1, thus diverting current from the generator 34 from the winding of the transmitting relay TR and applying current from the generator 38 thereto in a spacing direction. The tongue of the transmitting relay is thereby moved to its spacing-contact to repeat the spacing signal over the single line SL'. l

Upon the receipt of the succeeding marking signal over the duplex line, thetongue of. the

line relay LR leaves a spacing contact, thus reversing the direction of current through the winding of the transmitting relay whereby the itongue of the transmitting relay. moves .to'its marking contact. Since the tongues of the trans-' mitting and line relays have the same travel 1 period they reach the markingcontact of. their respective relays at the same instant soithat the locking winding 36 is short circuitedat thefsame instant that the marking signal isrepeated 'over the line SL, thus causing no overlap of the holding magnet with the repeated :marking signaI. As in the case of the single line repeater .the

travel time of the linerelay is part of the marking signal and the travel time of the transmitting relay is a part of the spacing signal.

Signals transmitted over the single line SL are repeated to the duplex line and since the line relay LR does not respond thereto, it is not necessary to provide means to prevent therepetitio'n of these signals back overthe single line.

Figure 3 shows a duplex half repeater similar to that shown in Figure 2 with the exception that a polarized pole changer PC is employed in place of the neutral pole changer of. Fig ure 2. The single line SL is connected through operating winding 30' of the pole changer to,

the contacts of the transmitting relay. The

marking contact of the relay LR is connected to one end of the locking. winding 36'iof.the

pole changer, the opposite end of the winding being connected through a variablev resistance 41 to a source of potential 42 and also through a resistance 43 to the ground e l. Whenthe' tongue of the line relay is on its marking contact, generators 32 and 4.2 are grounded through the tongue of the line relay and current is supplied from the generator 42 through the-locking winding 36 in a spacing direction to apply a spacing bias to the pole changing relay PC. When a spacing signal is received over the duplex line, the tongue of the line relay leaves its marking contact and immediately thereupon the ground 41 is removed from the generators 42 and 32,

and current flows from generator '32 through the locking winding 36 in a marking direction, to the ground 44, thus locking the tongue of the pole changing relay on its marking contact.

When signals are received overthe single line the operating winding 30 predominates over the biasing winding 36' in response to marking signals to move the tongue of the pole changer to its markingcontact and when the single line is opened to transmit spacing signals thereover, the biasing current supplied by the generator 42 moves the tongue of the pole changer to its spacing contact. r i:

With the arrangement shown, in Figure '3,v it will be noted that the marking-contact ofthe line relay controls current reversals through the locking winding of the pole. changer and that the spacing contact controls current reversals through the operating'winding of the transmitsending leg. The transmitting relay TR has a single operating winding, current reversalbeing resistance 6%;

controlled therethrough by the spacing contact and grounded tongue of the line relay. The

tongue of the transmitting relay is connected to the receiving leg. which includes a receiving instrument S. .The marking contact of the trans- -mitting relay is connected to a grounded source of potential-45,

J Thepole changerPC is provided with a biasing winding 46 for maintaining a spacing bias thereon. An operating winding 47 is also provided having. one end connected to a source of potential 48 and the other end connected to'the' grounded sending leg. The sending leg includes a key K and a receiving instrument S.

' This arrangement permits signals to he simul- .taneouslytransmitted over the duplex line to the :receiving leg and from the sending leg over the duplex line in the opposite direction. Signals received over the duplex line are repeated by the transmitting relay to the receiving leg and the -make-andi break signals transmitted by the sending leg are repeated as positive and negative Signals by the pole changer PC over the duplex line DL.

In Figure 5 I have shown a terminal duplex set combined with a multiple duplex-leg repeater .and;providingzfacilities for two loop sets each having separate receiving and sending legs.

The terminal duplex set comprises a line relay LR and a. pole changer PC. Ihe marking contact of the relay LR is connected to a grounded source :duplex line are thus repeated to the receiving legs of both loop sets and to the receiving instruments S1 and S2 thereof.

'I'he sending leg of loop set A extends from a ground 52 through the operating winding of a recording instrument S3, key K1, operating winding 53 of a leg relay R1 to the tongue of an intermediate relay IR; and from the marking contact thereof thru the winding of the pole changer PC of the terminal duplex set to a grounded source of potential. The sending leg of loop set E extends from a ground5i through the winding of a recording instrument S4, key Kz-and operating winding 55 of leg relay R21to the back, or spacing contact of the leg relay R1.

Relay R1 is provided with a locking Winding 56 having one end grounded and the other end connected to the marking contact of relay R2. Relay R2 is provided with a locking winding 57 having one end groundedand the other end connected to the marking contact of relay R1. The marking contacts of relays R1 and R2 are connected to grounded generators 58 and 59 respectively and the spacing contacts of relays R1 and R2 are connected to grounded generators 60 and 61 respectively. The spacing contact of relay R2 is also connect ed to one end of the operating winding oi the intermediate relay IR, the opposite end of this winding being connected to a grounded source of potential 62 and also to th'e'ground 63 through a Signals may be sen'tout over either one of the sending legs simultaneously with the receipt of signals over the duplex line and th signals transmitted by said sending leg will be repeated both to the duplex line and to the sending leg of the opposite loop set. For instance, if the key K1 of loop set A is opened to transmit a spacing signal, this signal is repeated by the pole changer to the duplex line. At the same time the tongue of relay R1 is released from its marking contact, thus removing the ground 65 from the generator 58 and causing the current to be supplied therefrom to the locking winding 57 of the relay R2 to hold its tongue on its marking contact. When the tongue or the relay R1 reaches its spacing contact the generator to becomes grounded at 65 and current falls to zero through the sending leg of the loop set E which is equivalent to the repetition of a spacing signal thereto. When thekey K1 is closed to transmit a marking signal, the tongue of relay R1 moves back to its marking contact, diverting current from the locking coil 57 of relay R2 and restoring current from the generator 60 to the sending leg of loop set B, to repeat the marking signal thereto.

When the key K2 of loop set B is'opened to transmit a spacing signal the tongue of relay R2 leaves its marking contact and through removal of the ground 66 frornthe generator 59, establishes a locking circuit for the winding 56 of relay R1, at the same time when the tongue of relay R2 strikes its spacing contact current from generator 61 is diverted to the established ground and current flows from generator 62 through the operating winding of th intermediate relay vIR in a spacing direction to repeat. the spacing signal through the contacts thereof to the pole changer PC. The movement of the tongue of the relay IR from its marking contact also repeats the spacing signal to the sending leg of loop set A. Upon closing of the key K2 to transmit a marking signal, the relay R2 is energized, removes the ground 66 from generator 61, and applies the ground .66 to the generator 59, thus releasing the locking magnet 56 and reversing the direction of current through the winding of the relay IR and thereby repeating the marking signal both to the duplex v line and to the sending leg of loop set A.

In this arrangement it will be noted that the marking contact of the relay R2 controls the circuit to the locking winding of the relay R1 and the spacing contact of relay R2 controls reversals of current through the winding of the intermediate relay IR.

It will be noted that the leg connections within the terminal duplex set are of'the same character as the legs themselves, that is they terminate in a ground or a grounded battery. As a consequence, another terminal duplex set may be substituted for one of the loop sets and the multiple duplex leg repeater thus utilized to connect two duplex circuits together at a repeating station and at the same time connect an intermediate operating station in the circuit. This intermediate operating station mayhe simply twolegs in the repeating station. ofiice or it may be a distant oflice at the end of another duplex circuit. In either case the intermediate station could receive from either or both terminal stationa but could transmit inv one direction only. The terminal station could work the duplex circuit both ways, of course.

The intermediate station would be connected in the way illustrated for loop set R, and the duplex set would be connected in the circuit in place of loop set A, the connections being arranged so that the pole changer would he in the receiving leg connection and the receiving relay of the duplex that of the corresponding received signal.

et oul be a ed t n inslee o nect n- While a number of. arrangements have ,been' shown embodying one or more featuresoi thetothe particular circuit arrangements disclosed and described, except in accordance with the;

appended claims.

What I cl m 5 2 1. A telegraph repeater set comprising a line relay, a polarized transmitting relay having an operating winding and means comprising the armature and a single contact of the line relay for obtaining current reversals through the operating winding of said transmitting relay.

2. A telegraph repeater set comprising a receiving relay and a repeating relay, said receiving relay through its armature controlling the operation of said repeating relay, and said repeating relay through its armature repeating the signals to a line, the travel time of the armature of the receiving relay in one direction being a part of either the repeated marking or spacing :signals and the travel time of the armature of the repeating relay in the opposite direction being a part of the other repeated signal, and the travel time of the armature of both relays being substantially the same, whereby the length of each repeated signal will be substantially the same as 3. A telegraph repeater set comprising a receiving relay, a polarized repeating relay and an operating winding for the repeating relay, said treceiving relay in response to signals transmitted thereto controlling through its armature and one only of its contacts, reversal of current through said repeating relay, the travel time of the armature of the receiving relay from its marking to its spacing contact being a part of the marking signal and the travel time of the armature of the repeating relay from its spacing to its marking contact being a part of the spacing signal.

4. A telegraph repeater set comprising a re- -ceiving relay and a repeating relay, an operating winding for said repeating relay, said receiving 'the contacts of said second relay for controlling relay in response to signals transmitted thereto eiiecting current reversals in said winding for controlling the operation of said repeating relay,

. .the armature of said repeating relay starting its movement from the marking to the spacing contact immediately upon the arrival of the armature of the receiving relay at its spacing contact and the armature of said repeating relay start- .ing its movement from its spacing to its marking contact when the armature of the receiving relay the reversal of current through the winding of said polarized relay.

6. A telegraph repeating set comprising two receiving relays, a repeating relay, an operating winding for the repeating relay, 2. locking circuit for one of the receiving relays, a source of current for said circuit, means for controlling said locking circuit comprising a shunt path for said source 0f current completed through the armature and "marking contact of the other receiving relay and means for controlling the operation of said repeating relay comprising a low resistance return path for the operating winding thereof, said path 7'5 being completed through the armature and spacing contact of the last mentioned receiving relay. ,;7.; Ina telegraph system, a polarized relay having an operating winding andmeans for obtaining current reversals through said winding, comprisinga source of potential of the same polarity connected to each terminal" of said winding, a. high resistance returnpath ior each of said sources, of potential connected to onev terminalofsaid winding and 'a low resistance return pathior each of saidsourc es of potential connectedftothe op posite' terminal of said and means: for" opening and closing said low resistance return path to obtain reversals in the direction of current in said operating winding.

8. A telegrapl'i repeater set comprising two receiving relays, a repeating relay, a locking circuit for one of said receiving relays, an operating circuit for said repeating relay, means compris ing the armature and marking contact of one of the receiving relays for obtaining reversals of current in the locking circuit of the other receiving relay and means comprising the armature and spacing contact of the'first mentioned receiving relay for obtaining current reversals in the operating circuit of the repeating relay.

9. A telegraph repeater set comprising a receiving relay, a repeating relay and a pole changing relay, said receiving relay responding to signals received over one line and said repeating relay repeating the signals over a second line, a locking circuit for said pole changing relay and means acting upon the receipt of a spacing signal by said receiving relay to energize the locking circuit to hold the armature of the pole changing relay on its marking contact and means acting.

simultaneously with the repetition of a marking signal over said second line to release said armature.

10. A telegraph repeater comprising two receiving relays, a repeating relay, a locking winding for one of said receiving relays, a grounded armature and a marking and a spacing contact for the other receiving relay, a grounded source of potential having one terminal connected to said locking winding and to said marking contact, a second grounded source of potential having one terminal connected to the winding of the repeating relay and to said spacing contact, whereby said first source of potential is shunted around said locking winding when said armature is on its marking contact and the second source of potential is shunted around the winding of said repeating relay when said armature is on its spacing contact.

11. In a telegraph system, a polarized relay, an operating winding therefor, a source of potential for applying current in a marking direction through said winding and a second source of potential for applying current in a spacing direction therethrough, a receiving relay and means controlled by a single contact of said receiving relay, acting upon the receipt of a marking signal to render said second source of potential ineiiective with respect to said winding and to apply current to said winding from the first source of potential and means acting upon receipt of a spacing signal to render said first source of potential ineffective with respect to said winding and to apply said second source of potential thereto.

12. In a telegraph system, a first line section, a second local section, a polarized line relay having a single winding, means to cause said relay to repeat signals from one line section to the other,

and electrical connections including a two-point 13'; In a telgra ph sys tm,'a,-jfirst V a 's'eo'nd line section, airjeivin'g relay having af inding connected i-h ohsectio'ii, a polaizfim'd ri-i-l'gi'y having a, single winding adapted to; trans-- WILLIAM 1 SPARKS; 

